灵芝酸A对人肝癌细胞的辐射增敏效应的初步研究

本研究旨在初步探讨灵芝酸A(GAA)对人肝癌细胞系HepG2在高LET中子和低LET的γ射线条件下的辐射敏感性的影响及差异。研究中,我们用CCK-8方法检测不同浓度GAA对HepG2增殖抑制作用。选取低浓度(5μmol/L)GAA预处理细胞24 h,分别给予不同剂量的中子辐照或γ射线辐照,分别检测克隆存活率、细胞凋亡和γH2AX蛋白的foci的形成。结果表明:在不加GAA的情况下,高LET中子辐射比低LET的γ射线对细胞产生的凋亡比例高;在添加了GAA后,与未加GAA对照组相比,诱导细胞凋亡的比例明显增加;另外,加GAA处理后,细胞增殖抑制率也随着辐照剂量的增加而增高。即GAA能增加HepG2细胞的辐射敏感性,而在同样GAA剂量下,HepG2细胞对高LET中子辐射比低LET的γ射线更敏感。由此,这项研究说明灵芝酸或可开发成为一种天然辐射增敏剂,从而为癌症特别是肝癌的放疗提供新的辅助治疗方法。     

Ultradilute self-bound quantum droplets in Bose–Bose mixtures at finite temperature

We theoretically investigate the finite-temperature structure and collective excitations of a self-bound ultradilute Bose droplet in a flat space realized in a binary Bose mixture with attractive inter-species interactions on the verge of meanfield collapse. As the droplet formation relies critically on the repulsive force provided by Lee–Huang–Yang quantum fluctuations, which can be easily compensated by thermal fluctuations, we find a significant temperature effect in the density distribution and collective excitation spectrum of the Bose droplet. A finite-temperature phase diagram as a function of the number of particles is determined. We show that the critical number of particles at the droplet-to-gas transition increases dramatically with increasing temperature. Towards the bulk threshold temperature for thermally destabilizing an infinitely large droplet, we find that the excitation-forbidden, self-evaporation region in the excitation spectrum, predicted earlier by Petrov using a zero-temperature theory, shrinks and eventually disappears. All the collective excitations, including both surface modes and compressional bulk modes, become softened at the droplet-to-gas transition. The predicted temperature effects of a self-bound Bose droplet in this work could be difficult to measure experimentally due to the lack of efficient thermometry at low temperatures. However, these effects may already present in the current cold-atom experiments.     

新型纳米铂修饰玻碳电极的制备及电催化性能研究

研究了一种新型纳米铂修饰玻碳电极的制备方法,并对其电化学催化性能进行了研究。实验结果表明,通过电沉积前在金刚石粉末悬浊液中对玻碳电极进行超声处理,可制备出新型玻碳电极。经超声处理后,金刚石颗粒在玻碳电极基体上产生了数微米长的划痕。电沉积过程中,在该电极上可沉积分布较密集的平均尺寸为110nm的Pt颗粒。这种新型纳米铂修饰玻碳电极的表面电化学活性值为0.397 m2/g,高于普通铂修饰玻碳电极,且在0.5 mol/L H2SO4溶液中具有良好的电化学稳定性。     

费谢尔判别法鉴别原油/燃料油

以多环芳烃作为变量,建立了原油、燃料油属性鉴别的费谢尔判别法。分别测定了来自不同国家和地区的26个原油样品和25个燃料油样品中8种多环芳烃的含量,并将它们作为判别变量。借助SPSS 16.0进行费谢尔判别分析,建立费谢尔判别函数。将未知样品的判别变量值代入后,可以快速地得知样品的类别。结果表明,以多环芳烃作为判别变量进行原油、燃料油费谢尔判别快速而准确。     

BENDING SOLUTION OF A RECTANGULAR PLATE WITH ONE EDGE BUILT－IN AND ONE CORNER POINT SUPPORTED SUBJECTED TO UNIFORM LOAD

ＢＥＮＤＩＮＧ　ＳＯＬＵＴＩＯＮ　ＯＦ　Ａ　ＲＥＣＴＡＮＧＵＬＡＲ　ＰＬＡＴＥ　ＷＩＴＨ　ＯＮＥ　ＥＤＧＥ　ＢＵＩＬＴ－ＩＮ　ＡＮＤ　ＯＮＥ　ＣＯＲＮＥＲ　ＰＯＩＮＴ　ＳＵＰＰＯＲＴＥＤ　ＳＵＢＪＥＣＴＥＤ　ＴＯ　ＵＮＩＦＯＲＭ　ＬＯＡＤＸｕＱｉｌｏ...     

煤矿顶板离层回归分析与稳定性评价

以光纤Bragg光栅位移传感器对淮北朱仙庄煤矿顶板离层监测为实际数据依据,选择最佳的典型函数模型对顶板离层进行非线性回归分析,得出能够反映位移发展趋势的回归曲线。监测结果与回归拟合数据表明:非线性回归分析预测方法不仅可以反映煤矿顶板离层实时变化过程,还能根据其变化趋势进行巷道稳定性判断。     

Effect of far-field flow on a columnar crystal in the convective undercooled melt

The growth behavior of a columnar crystal in the convective undercooled melt affected by the far-field uniform flow is studied and the asymptotic solution for the interface evolution of the columnar crystal is derived by means of the asymptotic expansion method.The results obtained reveal that the far-field flow induces a significant change of the temperature around the columnar crystal and the convective flow caused by the far-field flow accelerates the growth velocity of the interface of the growing columnar crystal in the upstream direction and inhibits its growth velocity in the downstream direction.Our results are similar to the experimental data and numerical simulations.     

微腔中两原子缀饰态的二光子衰变

研究了微腔中原子衰变问题。考虑微腔中存在两个原子，两原子与腔场强耦合形成的缀饰原子与腔壁相互作用在特定初始条件下的衰变问题，指出在腔场中该衰变方式下，腔场光子数越多、衰变则越强     

光学电功率传感器研究综述

综述了现有各种光学电功率传感器的传感机理和主要特点,提出了电功率传感器研究中存在的问题、方法和研究方向。光学电功率传感器一般具有测量范围大、响应频带宽和电气绝缘能力强等优点。根据光载波中是否含有电功率调制信号,可将光学电功率传感器分为直接调制型和间接调制型两类;与光学电压、电流传感信号相比,直接调制型光学电功率传感信号更加微弱,且其有功功率传感信号为直流信号,易与光载波强度波动混淆。对于单晶体型电功率传感器,一般要求传感介质兼具线性电光、磁光效应,或者具有双横向电光Pockels或Kerr效应;此外,选择传感介质时应全面考虑其多重光学效应及其相互关系,并应考虑如何避免或抑制传感信号的温度漂移。光学电功率传感器在智能电网、微波功率及电磁脉冲功率测量等领域具有潜在的应用前景。     

以硫酸镓/凹凸棒固体酸为催化剂的肉桂酸乙酯合成综合制备实验设计

利用自制硫酸镓/凹凸棒固体酸催化剂代替浓硫酸,设计了肉桂酸乙酯合成综合制备实验,该实验由肉桂酸制备、硫酸镓/凹凸棒固体酸催化剂制备、肉桂酸乙酯合成、肉桂酸乙酯酯化率测定等部分组成。当肉桂酸乙酯合成条件为肉桂酸7.5 g、无水乙醇18 mL、反应温度120 ℃、反应时间3.0 h时,肉桂酸乙酯的酯化率不低于85%,所制催化剂经7次重复使用,肉桂酸乙酯的酯化率仍达42.3%。实验克服了浓硫酸催化法存在的缺点,具备显著的综合实验特征。